#include <conio.h>
#include <stdio.h>
int tinhS(int n){
	
	int sum = 0;
	for( int i = 1; i <= n ; i++){
		sum += i;
	}
	return sum;
}
int tinhSDeQuy(int n){
	if( n == 1) return 1;
	else return tinhSDeQuy(n-1) + n;
}
int main(){
	printf("%d", tinhS(10));
	printf("\n%d", tinhSDeQuy(10));
	getch();
}
